If Preferred Enemy does work on shooting then Tomb Blades will happily throw around S6 blasts. Regular Destroyers took a huge nerf to their guns such that whatever you can do with them now can probably be done better with another unit.
Other than potential model purchases I don't see the point in discussing a change that won't happen for 6-7 months.
HDs are still good, highly mobile AT.
Warriors are durable as long as the unit size stays up. I've seen a lot of Necron players try to field 5-8 man squads, usually as Cryptek bunkers or objective holders. Smallarms quickly put the whole unit down thanks to the lower armour - RP then becomes irrelevant.
Larger units with an Ark or Res Orb are better, naturally. I have more difficulty dealing with Plague Marines. They are by no means fragile but I don't see where they have "truly phenomenal durability".